Sigmen said:
Quite a lot of writing, I may prefer clearer, and more explicit words rather than excessive rambling. Let's go thought.
First, those Kenjutsu techniques are not based on "manuals", for they are taught in Kenjutsu Dojo, from generations of teachers to generations of teachers. Some changes in interpretation are true, but they are not to be rediscovered from scratch.
Generally, ancient European blades were indeed not as sharp as Japanese swords ; knowing how much effort was put into sharpening one blade in Japan.
However, the reason why they were not as sharp was simple ; whilst Japanese blades had hamon, differential hardening, and used that "pig iron" as so called by detractors on the edge generally ; that allowed great hardness and edge retention European swords did not ; therefore not as good at edge retention.
They were therefore not as sharpened (thought with with enough time you can sharpen any piece of metal to a great degree, however, if too soft it will loose the edge. If too hard, brittle).
However ; if Longswords were dependent on blunt trauma as you suggested. Then ; why not favor simply a hammer ? In fact, the very fact that Longswords are weighting on average between 1100g and 1800g which is definitively light compared to the weapon's size, and it's close-to-the-handle balance would not allow to deliver great blunt trauma therefore, for me, proving how much cutting was important.
The technique using a sword like a hammer was called Mordhau, and since the point of balance is near the handle allowed for much better blunt power. Exactly what makes sense, strike with the point of balance where the most power would be delivered.
Nice point in there ;
This is also due to the different use of those weapons. In medieval europe, where the norm was to capture knights to ransom them, killing weapons were not sword or even axes but dagues and dirk which were renowed as "infamous" weapons attributed to routier and throat-cutter.
However, the main reason why knights did not die as much was not ineffective weapons, as much as the incredible protection their armors gave them against the most dangerous types of attacks (trust, cuts to the torso, stomach, neck, head ; all very well protected). The best armor's protection way outclassed weapon capacity.
For example just on the picture right up there. Give me the best sword you have, and train me in cutting for ten years. I can't, just, definitively, even then can't kill him with my best strike for I'd barely glance, or dent some steel and break my blade unless I strike a weak point. And weak points won't be generally to parts that would kill the person.
Even further, the difference in hardness between Japanese and European blades was not that important.
Generally, later-era European blades with spring steel had very durable blades, with negligibly worse cutting power, but the kind of blades that were very strong and resilient. And, older types of blades, whilst softer, were definitively great cutters and rather resistant ; since softer blades would bend rather than break.